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#301
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We are going to chamfer all rear main bearing no matter what from now on!Tom
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#302
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dmac - Ditto what Tom S said. Chamfer the bearings as a precaution.
Also, I'd have the rotating assembly balanced locally.
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#303
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dmac - You can at least spin it, remove the caps and check one side of the bearing for witness marks on the edge. I'd have a helper pry the crank forward and back a bit as it spins.
What I don't know, is whether we should be concerned about all the main bearings, or just #5. From my machinist, only the new style Clevite #5 is located poorly. According to Butler, it is all bearings.
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#304
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Quote:
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65 Tempest, 400, TH400 86 Fiero SE 2.8 |
#305
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Been thinking about the Butler response to this condition being core shift and that being dismissed out of hand by everyone in the thread. While I agree a machining error in tang location or the crankshaft is the most likely cause, IMO core shift is a possibility. Here is how. The main saddles are part of the multiple cores assembled in the core box for the block. During the pour of there was a minor shift in the core box, one or more of the main saddles could be slightly out of position. When it was originally line bored and assembled with a cast OE crankshaft with almost no fillet radius it may have just barely cleared and run without issue. When the Scat crank was installed with the large radius, everything changed as far as fitment and minimum clearance and then the failure. So , I am saying core shift is possible. It's something I have never seen in the #5 of a Pontiac, but I learn new things every day. I will sure be looking more carefully in that area now.
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#306
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mgarblik - Maybe.
For me, I am trusting the machinist on this. He told me that he is sure, with certainty, that it is a #5 Clevite bearing issue. He has compared it older style Clevite bearings and modern FM bearings. He has bearings there now, 3", 3.25", standard and 10 under. Also, he has the Clevite rep involved, whom respects his diagnostic abilities enough to come to the shop and now has scheduled a revisit to pursue this as a QC issue. Also, I want everyone to know that is reading this, that my only request of Butler was to contact Clevite, as a reseller, on my behalf regarding the QC issue. I told them that the local Clevite rep is involved and gave them the contact info of my machinist. It would be great, if out of this debalcle, Clevite would introduce a more chamferred and/or narrow bearing for aftermarket forged crankshafts.
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#307
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I agree with you. It's great that a Clevite rep is interested enough to get involved. It is also in their best interest to determine if it is in fact a bearing problem so they can recall effected bearing sets, or at least get the word out to vendors, shops and customers to check for a defect if one is found. Not doubting your machinist at all. If Joe Sherman was involved with this shop I would trust them absolutely.
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#308
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23 years ago, 1997! I've tweaked it over the years. I need to do another update, and get it to John to host.
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'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust My webpage http://lnlpd.com/home |
#309
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I spoke to my machinist yesterday, and the long block will be ready for me to pick up the week after Thanksgiving... So, I should have it installed and running by Christmas.
He will be using FM bearings this time around! Some other interesting points from the machinist. The camshaft woodruff key didn't sit well in the groove and I broke one cam gear on install, and another on disassembly. The machinist uses a non-Pontiac one that has a flat bottom and nests better, solving this issue. Also, he doesn't like the composite dizzy gears. I had a BOP one I was going to put on, but he thinks a gear that matches the camshaft alloy is best. Anyway, I'm excited to get this project moving forward. I'll post photos when the time comes.
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#310
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“The camshaft woodruff key didn't sit well in the groove and I broke one cam gear on install, and another on disassembly. The machinist uses a non-Pontiac one that has a flat bottom and nests better, solving this issue”
Say what?.........please post a pic of the cam that was removed....especially the cam snout and key way. This seems highly unusual? If the cam was indeed broken on install, you have the catalyst for the rest of the damage?
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71 GTO, 463, KRE 295 cfm heads ported by SD Performance, RPM intake, Qjet, Dougs Headers, Comp cams HR 246/252 ...11 to 1 , 3.55 cogs, 3985lbs.....day three- 11.04 at 120mph ....1.53 60', 6.98 1/8 mile |
#311
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No, you misunderstood me.
On my initial assembly, I chipped the cam gear where it indexes with the woodruff key. I, of course, didn't proceed to use that timing set. I had a backup timing set, which I installed, no problems. When the engine grenaded, I had to disassemble the engine, and when I pried off the timing set, I chipped the cam gear in the same place. These were both cast cam gears. My analysis led me to believe there was an issue with my camshaft, with the groove in which the camshaft woodruff key nests. I relayed this to the machinist. He replied that he has for years used a flat bottom woodruff key for this reason. They nest cleanly and flat in the camshaft. I was relaying that bit of info. It is a small detail I would not have known as a 1st timer, but would have saved me some grief and money. It had nothing to do with my engine failure.
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#312
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Quote:
Have you found cause and effect yet?....thought you spoke with a bearing rep or two? Any info? I run Clevite bearings on my build, so I’m curious.
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71 GTO, 463, KRE 295 cfm heads ported by SD Performance, RPM intake, Qjet, Dougs Headers, Comp cams HR 246/252 ...11 to 1 , 3.55 cogs, 3985lbs.....day three- 11.04 at 120mph ....1.53 60', 6.98 1/8 mile |
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